Radius grinders



Nov. 29, 1955 J. GRABOWY RADIUS GRINDERS 2 Sheets-Sheet 1 Filed Sept. 16. 195.3

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5. J a m w H Nov. 29, 1955 J. GRABOWY 2,724,933

RADIUS GRINDERS 2 Sheets-Sheet '2 Filed Sept. 16. 1953 ATTOR/Vi) United States Patent 9 RADIUS GRINDERS.

John Grabowy, Chicago, 111., assignor to Western Electric Company, Incorporated, New York, N. Y., a corporation of New York Application September 16,,1953, Serial No. 380,565

Claims. (Cl. 51'-.-I24)' This invention relates to radius grinders, and more particularly to work-holders for grinders.

An object of the invention. is to. provide, new and. improved radius. grinders.

Another object of the invention is to provide new and improved work-holders for grinders.

A further object of the invention is. to provide work.- holders which may be rapidly set to grind any desired? radius.

A radius. grinder illustrating certain features of the. invention may include a square base plate mounted rotatably about an axis transverse to the plane thereof and centered relative to the plate. A square holder plate is mounted on. the base. plate adjustably along a line diagcoal to both plates. A workpiece having a corner to be ground to a radius is placed on the holder plate. with the corner aligned with said axis. The holder plate then may be adjusted along the diagonal of the base plate. for oifsetting the corner from the axis of rotation of the base plate for grinding a predetermined radius thereon.

A complete understanding of the invention may be obtained from the following detailed description of a radius grinder forming a specific embodiment thereof, when read in conjunction with the appended drawings, in which:

Fig. 1 is a fragmentary, plan view of a radius grinder forming one embodiment of the invention;

Fig. 2 is a fragmentary, plan view of the grinder shown in Fig. 1 with parts thereof in different positions;

Fig. 3 is an enlarged, fragmentary top plan view of a portion of the apparatus;

Fig. 4 is a vertical section taken along line 44 of Fig. 2, and

Fig. 5 is a vertical section taken along line 5-5 of Fig. 2.

Referring now in detail to the drawings, there is shown therein a grinder for grinding a predetermined arcuate curve on a square post 11 projecting from a base 12 of a workpiece 13, a corner 14 to be ground away. The grinder includes a carrier adjustable by conventional means (not shown) in a direction parallel to the face of a grinding wheel 21 and also adjustable by conventional feed means (not shown) in a direction transverse to the face of the wheel 21. A square plate 22 is mounted rotatably on a pin 23 secured to a base 19 secured to the carrier and may be pivoted between adjustable stops 24 and 25 mounted on the base 19. Bolts 26 are threaded into a T-shaped guide bar 27 mounted in an undercut groove 28 of T-shaped cross-section and formed in the square plate 22 to secure a second square plate 32 to the square plate 22, the bolts 26 fitting into counterbored holes 33 in the plate 32. The bolts 26 are normally tightened to prevent relative movement between plate 32 and plate 22.

The groove 28 extends diagonally from one corner of the square plate 22 to the opposite corner and the holes 33 are so positioned in the plate 32 that the plates 32 and 22 may be lined up with the plate 32 directly over the plate 22, the plates 32 and 22 being of the same ice 2 dimension on each side thereof. The. bolts 26- on. threaded from the guide bar 27 to permit the plate 32 to.- be slid along the groove, 28 to oifset, the plate. 32 from the plate 22 in a direction diagonal to these; plates. The. plate; 32 is provided with a plurality of tapped bores. 41 into which cap screws. 42 may be threaded to secure clamps 43 in any desired. positions to the plate 32, and. screws 44 may be screwed further into the. clamps 431m bear against the. plate 32 and press the. opposite: ends. of: the. clamps- 43 downwardly toward the plate 32? to clamp the workpiece 13- to the plate 32. L-shaped gauge. plates 4'5 temporarily bolted to adjacent sides of the plate 22 are provided with overhanging; arms 464.6 which project. over the plates. 32. and 22 exactly one-half the length of one of the sides of the plates 22 and 32, and form therebetween. a corner into. which the corner.- 14 isv titted before. the clamps 43; are. actuated to precisely locate the corner 14 of the workpiece, 13- over the: center of, the plate 32,. which at: this. time is, directly over the center of the pin 23. The gauge plates: 45 are removed from plate 22 after the workpiece. 13- has been clamped in its: Gem teredz position and before plate 32. is moved to. provide. the desired radius.

After the workpiece. 13 has been clampedon the; plate.

321 with the corner 14: of the post, 11 aligned with the.

- center of the plate. 32, the platev 3.2. is unclamped from the;

plate. 22 and is slid diagonally along the groove, 28 u h a. distance as. to provide. the desired radius of the curve 10 which is determined by measuring the distance from aside surface: 51v of the. plate 32 and aside surface 52 of the plate 22, or by thedistance. of a side surface 53. of

the plate 32. to a side. surface 54 of the plate 22, which distances. are. the same. The carriage 20* then; is moved to a position in which the axis of rotation of the plates 22 and 32 intersects the projected axis of the grinding wheel. Then, the carriage is moved laterally toward the wheel and successive cuts are taken from the corner 14, the plates 22 and 32 being swung for each cut. The carriage, of course, is fed incrementally toward the grinding wheel between cuts until the arc is tangent to the adjacent sides of the post. A corner of the plate 22 is cut away to provide clearance for the stops 24 and 25 to permit the plate 22 to be swung a full as illustrated in Fig. 2 an uncut corner of plate 22 is in abutment with the stop 25. From this position the plates are rotated clockwise until the other uncut corner of the plate 22 abuts with the stop 24, moving the corner 14 past the grinding wheel face 21 as shown in Fig. 3. As the plates are oscillated from stop to stop, the grinding wheel 21 is advanced toward the workpiece post 11 until the ground are 10 is tangent to the adjacent sides.

The above-described apparatus is simple in construction and operation, and also is very precise in grinding desired curves.

It is to be understood that the above-described arrangements are simply illustrative of the application of the principles of the invention. Numerous other arrangements may be readily devised by those skilled in the art which will embody the principles of the invention and fall within the spirit and scope thereof.

What is claimed is:

1. A radius grinder, which comprises a square mounting plate, means supporting the mounting plate for rotation about an axis through the center of the square thereof, a work-holding plate of the same square dimensions as the mounting plate, means mounting the work-holding plate directly over the mounting plate for adjustment along a diagonal common to both plates, and means for securing a workpiece on the work-holding plate.

2. A radius grinder, which comprises a square, rotatable mountiug plate having a diagonal guideway, a workholding plate of a shape identical with that of the mounting plate, means slidable along the guideway in the mounting plate for locating the work-holding plate on the mounting plate, means for clamping a workpiece to the work-holding plate in a position in which one corner of the workpiece is centered with respect to the work-holding plate, and means for grinding said corner as the plates are oscillated.

3. A radius grinder, which comprises a square, rotatable mounting plate having a diagonal guideway, an identically shaped work-holding plate slidable along the guidewayin the mounting plate, a pair of gauges for locating a corner of a workpiece at the center of the workholding plate, releasable means for locking the workholding plate against movement along the guideway, and means for clamping the workpiece to the work-holding plate in a position in which one corner of the workpiece is centered with respect to the work-holding plate.

4. In a radius grinder including a grinding wheel and a carriage movable toward and away from an operative face of the grinding, a work-holding device designed to be mounted on the carriage comprising a mounting plate of a predetermined square shape mounted pivotally on the carriage onan axis through the center of the plate, a work-holding plate of a square shape identical with the square shape of the mounting plate, one of said plates having a diagonal undercut groove extending across one face thereof, releasable locking means cooperating with the groove for holding the other plate selectively in any desired position ranging from the work-holding plate being centered over the mounting plate to a position in which the work-holding plate is substantially offset diagonally from the mounting plate, a pair of L-shaped gauges having arms of a length equal to one-half the square dimension of the plates, means for temporarily locking the gauges to adjacent sides of the mounting plate on opposite sides of said diagonal in positions in which the arms of the gauges overhang the Work-holding plate and serve as stops to locate a rectangular workpiece with a corner centered over said pivotal axis, and means for clamping the workpiece to the work-holding plate in said position of the workpiece.

5. In a radius grinder including a grinding wheel and a carriage movable toward and away from an operative face of the grinding, a work-holding device mounted on the carriage comprising a mounting plate of a predetermined square shape, means supporting the mounting plate pivotally on the carriage about an axis through the center of the plate, a work-holding plate of square shape identical with the square of the mounting plate, said mounting plate having a groove of T-shape in cross-section extending diagonally across the mounting plate, an elongated bar fitting slidably in the groove, means securing the bar to the work-holding plate for clamping the work-holding plate to the mounting plate in any desired position ranging from the Work-holding plate being centered over the mounting plate to a position in which the work-holding plate is substantially offset diagonally from the mounting plate, a pair of L-shaped gauges having arms of a length equal to one-half the square dimension of the plates, means for temporarily locking the gauges to adjacent sides of the mounting plate on opposite sides of said diagonal in positions in which the arms of the gauges overhang the work-holding plate and serve as stops to locate a rectangular workpiece with a corner centered over said pivotal axis, and means for clamping the workpiece to the work-holding plate in said position of the workpiece.

References Cited in the file of this patent UNITED STATES PATENTS 1,919,545 Fisher July 25, 1933 2,395,598 Weaver Feb. 26, 1946 2,404,465 Statia July 23, 1946 2,554,530 Hosinski May 29, 1951 

